The invention relates to a tip, more in particular to a tip for attachment to a bottom end of a foundation pile. The invention also relates to a method for manufacturing such a tip, as well as a foundation pile assembly that makes use of such a tip.
A tip for an on-site formed foundation pile assembly is, for example, known from U.S. Pat. No. 4,623,025 and EP0855489. Such a tip is also called drill tip, and is attached to the bottom end of a foundation pile. The tip is preferably designed as a cast iron structure since this facilitates the production of a suitable shape, in particular of, for example, spiral ribs which are arranged to the surface of the tip. In order to couple the tip to the bottom end of the foundation pile, the tip is provided with cam-shaped structures that couple into corresponding recesses at the bottom end of the foundation pile. This offers the advantage that the foundation pile can be removed again after the formation of an on-site poured concrete foundation pile, such that only the tip and the concrete foundation pile remain behind in the ground layer. However, for certain applications, for example, wherein the foundation pile assembly is used in an environment with a water layer, a swampy area, etcetera there is the need to make use of a tip that is fixedly coupled to the foundation pile assembly to avoid inflow of water into the foundation pile assembly during entering into the ground layer and during the formation of an on-site formed concrete foundation pile. In addition, there is also the desire to achieve an improved anchoring of the tip to the bottom end of the foundation pile in an effort to be able to withstand higher pressure forces and torques upon entering of the foundation pile assembly in the ground layer.
Furthermore, it is not easy to achieve a welded joint between a cast iron tip and a steel foundation pile at a construction site where a foundation pile assembly should be assembled on the basis of delivered foundation piles and tips as this requires welding operations and associated equipment which are normally not at disposal at a construction site.
A tip for a foundation pile is further known from FI85901B. This foundation pile assembly comprises a tip for the bottom end of a pre-manufactured concrete foundation pile, in which a tip element is attached at the bottom end of the tip. Such a type of tip makes it possible, in particular in circumstances in which the support surface is rocky, to distribute the tension at the height of the bottom end of the foundation pile as uniform as possible in order to avoid uneven peak loads as much as possible. However, the manufacture of such a tip requires a plurality of welding operations for the manufacture of the tip body. It is also necessary for the arrangement of the tip element to the tip body that sufficient clearance and an associated attachment element such as, for example, a bolt are provided. This clearance and associated tolerances ensure that at high loads the anchoring of the tip element is not optimal and therefore unwanted peak loads can still arise. Moreover, it requires additional manual or mechanical operations in order to be able to attach the tip element.
Furthermore, a tip is also known from WO2011/075772, wherein in an exemplary embodiment is described that, in order to allow the welding of a tip to a foundation pile, it is desirable to manufacture the tip from cast steel. However, cast steel is a much more expensive material than cast iron. Such a cast steel tip is also more difficult to manufacture since the molding process, for example, requires higher melting temperatures.